General visible light communication is performed by transmitting, at a transmitter, visible light using a Light Emitting Diode (LED), a Laser Diode (LD), etc., as a light source and processing, at a receiver, the visible light using a Photo Detector (PD), etc. As the light emission efficiency of the LED is improved and the cost thereof decreases, the LED has become common in use in the general-lighting market such as fluorescent lamps, glow lamps, etc., as well as the special-lighting market such as portable devices, display devices, vehicles, sign lamps, signboards, etc.
In particular, the market of large-size signboards is continuously growing. In the large-size signboard market, the market of signboards using large Liquid Crystal Display (LCD) screens is also growing. The signboard is also called a Digital Information Display (DID), a Digital Signage (DS), a Large Format Display (LFD), or the like. For example, the DID device, by integrating display and Information Technology (IT) functions into conventional functions of posts using paper media and unidirectional advertisements using broadcasting, innovates the paradigm of information delivery through bidirectional communication between users and providers, such that the DID device has been in the limelight in its effects and cost reduction in the long run when compared to conventional delivery media. Recent DID technology has expanded its business area to the exterior advertisement and three-dimensional (3D) fields, through which general public can easily access advertisement media to which the DID solution is applied.
Various information display devices having display units, as well as the DID device, adopt LEDs in Back Light Units (BLUs). Since the LEDs may also be used as light sources for visible light communication, research is needed on information display devices having convenient and various functions using the BLUs adopting the LEDs.
As the number of information display devices using the LEDs in the BLUs increases, visible light communication using the LEDs is being actively studied.
However, in the information display devices such as the DID device, the LED transmits visible light, thus operating as a visible light transmitter, but till now, any service using visible light communication has not been proposed.
Moreover, considering that information display devices as well as the DID device are gradually connected through a network, a relationship with a server for continuously updating a new material in and managing the DID device needs to be defined.